The Brain Imaging Core has been added to this project because of the extraordinary developments in brain imaging using MRI over the last five years. Not only do the images provided excellent anatomical information but we can now obtain local metabolic information as well. The combination of the two types of information has the potential of serving as new biomarkers of risk and disease progression in Alzheimer's disease, particularly when used in conjunction with the other markers we have identified in previous cycles of this grant. The non-invasive character of the exam is particularly important for prospective epidemiological studies in an elderly population as are proposed here. The Core will be using a t.5T research scanner, part of the recently developed neuroimaging program at Columbia and applying both standard imaging procedures and techniques to measure local basal metabolism in the brain based on the relationship between metabolism and cerebral blood volume (CBV) which will be determined from Gadolinium difference images. We have extended this technique to allow measurement of the CBV in hippocampal subregions. The standard anatomical images will be sent to Dr. Charles DeCarli at UC Davis for volumetric analysis (total cerebral volume, volume of white matter hyperintensities, CSF volume, and volumes of the hippocmnpus and entorhinal cortex and stroke location and volume). The basal metabolic data will be estimated from local CBV calculated from difference images pre and post Gadolinium injection for subregions of the hippocampus (entorhinal cortex, subiculum, CA 1 and the dentate gyrus). The resultant volumetric and metabolic data will be entered into an Excel file and forwarded to EDMS Core. There are five specific aims: l. Acquire high quality anatomic and CBV images from the WHICAP cohort. 2. Archive the MRI data onto a RAID system and individual subject optical disks. 3. Transfer the anatomical images to Dr. Charles DeCarli at UC, Davis for volumetric analysis. 4. Calculate CBV in the subregions of the hippocampus and globus palladus. 5. Collect data from Dr. DeCarli's analysis and the basal metabolic estimates from Specific Aim 3 and input them into the project database maintained by the EDMS Core.